Power and Cost Estimate of Scalable All-To-All Topologies With Silicon Photonics Links
Luca Ramini
HPC, US
ABSTRACT
For many applications that require a tight latency profile, such as machine learning, a network topology that does not leverage arbitration-based switching is desired. All-to-all (A2A) interconnection networks enable any node in the network to communicate to any other node at any given time. Many abstractions can be made to enable this capability such as buffering, time-domain multiplexing, etc. However, typical A2A topologies are limited to about 32 nodes within one hop. This is primarily due to limitations in reach, power consumption and bandwidth per interconnect. In this presentation, a topology of 256 nodes and beyond is considered by leveraging the many- wavelengths-per-fiber advantage of DWDM silicon photonics technology. Power and cost estimate of scalable A2A topologies using silicon photonics links are provided in order to understand the practical limits, if any, of a single node communicating with many other nodes via one wavelength per node.
